U.S. patent number 4,124,302 [Application Number 05/775,854] was granted by the patent office on 1978-11-07 for device for photometering a substance placed in a cylinder-shaped cell.
This patent grant is currently assigned to Novosibirsky Institut Organicheskoi Khimii Sibirskogo Otdelenia Akademii. Invention is credited to Sergei V. Kuzmin.
United States Patent |
4,124,302 |
Kuzmin |
November 7, 1978 |
Device for photometering a substance placed in a cylinder-shaped
cell
Abstract
A device for photometering a substance placed in a
cylindershaped cell, comprising an aperture diaphragm and an
elliptical mirror successively arranged in the path of a light beam
emitted by a light source. The elliptical mirror is installed
coaxially to the cylindershaped cell containing the substance to be
photometered. The light beam, incident on the eliptical mirror and
reflected therefrom, is focused on said cell and then collected on
a photoreceiver. In the path of the light beam, incident on the
elliptical mirror and reflected from said mirror, is arranged a
semi-transparant mirror is arranged for directing the light beam
passing through said cell to the photoreceiver. The device has low
sensitivity to axial displacement of the cell with respect to the
optical axis thereof, and also exhibits low sensitivity to rotation
of said cell about its axis.
Inventors: |
Kuzmin; Sergei V. (Novosibirsk,
SU) |
Assignee: |
Novosibirsky Institut Organicheskoi
Khimii Sibirskogo Otdelenia Akademii (Novosibirsk,
SU)
|
Family
ID: |
37758699 |
Appl.
No.: |
05/775,854 |
Filed: |
March 9, 1977 |
Foreign Application Priority Data
|
|
|
|
|
Mar 11, 1976 [SU] |
|
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2337479 |
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Current U.S.
Class: |
356/440; 250/573;
359/839; 359/857 |
Current CPC
Class: |
B60Q
11/00 (20130101); G01N 21/255 (20130101) |
Current International
Class: |
G01N
21/25 (20060101); G01N 021/24 () |
Field of
Search: |
;356/207,208,103,180
;250/573,343,373 ;350/293 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Corbin; John K.
Assistant Examiner: Rosenberger; R. A.
Attorney, Agent or Firm: Lackenbach, Lilling &
Siegel
Claims
What is claimed is:
1. A device for photometering a substance placed in a
cylinder-shaped cell comprising: a light source; a light beam
emitted by said light source; an aperture diaphragm arranged in the
path of said light beam for limiting said light beam; an elliptical
mirror arranged in the path of said light beam beyond said aperture
diaphragm, and coaxially with said cylinder-shaped cell containing
a substance to be photometered for focusing said light beam on said
cell; and a photoreceiver, in the path of said light beam after
said light beam has passed through said cell and has been collected
by said elliptical mirror and thereafter reflected by a
semi-transparent mirror, for producing a signal proportional to the
amount of light passing through said cell.
2. A device as claimed in claim 1, wherein said aperture diaphragm
is ring-shaped.
Description
The present invention relates to optical measuring devices, and,
more particularly, to devices for photometering a substance placed
in a cylinder-shaped cell, which can be advantageously used in
medicine, biology and chemistry for qualitative and quantitative
analysis of microquantities of substances.
At present, stringent accuracy requirements are imposed on devices
for photometering substances placed in replaceable cylinder-shaped
cells. This is due to the extremely high sensitivity of said
devices, and to the accuracy of the positioning and geometry of the
replaceable cells.
Known in the art are devices for photometering a substance placed
in a cylinder-shaped cell, characterized in that the optical axis
of a device is perpendicular to that of the cylinder-shaped
cell.
Also known in the art is a device for photometering a substance
placed in a cylinder-shaped cell, comprising a light source and an
aperture diaphragm arranged in the path of a light beam emitted by
said light source, said diaphragm being intended for limiting said
light beam, which light beam is then focused on the cylinder-shaped
cell containing the substance to be photometered, and passes
through said cell, and is collected on a photoreceiver.
In said device, the light beam, limited by the aperture diaphragm,
is focused by means of a condensor (lens) on the cylinder-shaped
cell containing the substance to be photometered, which condensor
is interposed in the path of the light beam past the aperture
diaphragm. The light beam, which has passed through said cell, is
then collected by a similar condensor interposed in the path of the
light beam intermediate of said cell and the photoreceiver.
The above devices are extremely susceptible to the positioning and
shape of the cylinder-shaped cell, which can change, e.g., when
scanning or replacing the cell, thus affecting the reproducibility
of the photometering results.
It is an object of the present invention to provide a device for
photometering a substance placed in a cylinder-shaped cell, having
low sensitivity to both the positioning and to any imperfection in
the shape of said cell.
These and other objects of the invention are attained by providing
a device for photometering a substance placed in a cylinder-shaped
cell, comprising an aperture diaphragm arranged in the path of a
light beam emitted by a light source for limiting same. The beam is
focused on the cylinder-shaped cell containing the substance to be
photometered, passes through said cell, and is collected on a
photoreceiver. An elliptical mirror focuses the light beam which is
incident thereon, on the cylinder-shaped cell containing the
substance to be photometered, and also collects the light beam
reflected from the elliptical mirror after said beam has passed
through said cell. The mirror is positioned coaxially to said cell,
and a semi-transparant mirror is arranged in the path of the light
beam, incident on the elliptical mirror and reflected therefrom,
for directing said light beam, which has passed through the
cylinder-shaped cell, to the photoreceiver.
It is preferable that the aperture diaphragm should be annular so
as to provide for axisymmetrical illumination of the
cylinder-shaped cell containing the substance to be photometered,
and prevent illumination of the end face of said cell and the
portion of the elliptical mirror, proximal to said cell.
The proposed device for photometering a substance placed in a
cylinder-shaped cell has low sensitivity to the axial displacement
of said cell in respect to the optical axis of the device and is
not sensitive to the rotation of said cell about its axis. Said
device allows the use of cells very small in diameter
(capillaries), which make it possible to analyze microquantities of
substances.
The features and merits of the present invention will be more
readily understood from a consideration of a detailed description
of a preferred embodiment thereof to be read in conjunction with
the accompanying drawing illustrating an optical diagram of a
device for photometering a substance placed in y cylinder-shaped
cell (a partial longitudinal section), according to the present
invention.
The proposed device for photometering a substance placed in a
cylinder-shaped cell comprises a light source 1, emitting a
luminous flux which is shaped into a light beam 2 by means of a
condensor which is a lens 3. In the path of the light beam 2, past
the lens 3 and in immediate proximity thereto, an annular aperture
diaphragm 4 is arranged for limiting the light beam 2.
In the path of the light beam 2, past aperture diaphragm a
collective lens 5 is arranged, The aperture diaphragm 4 is
ring-shaped and is located in the focus of the collective lens 5.
In the path of the light beam 2 there is also arranged a field
diaphragm 6 which is in the focus of the lens 3 and in one of the
foci of an elliptical mirror 7 arranged further along the path of
the light beam 2. In the second focus of the collective lens 5, the
elliptical mirror 7 is arranged with its axis coaxial to a
cylinder-shaped cell 8, containing a substance to be photometered
9. This substance absorbs light within the range of the working
wave lengths. In the present embodiment, the substance is a liquid.
The elliptical mirror 7 is intended for focusing the light beam 2,
on the cylinder-shaped cell 8, and collecting said light beam 2,
reflected from the elliptical mirror 7 after said beam 2 has passed
through said cell 8. The aperture diaphragm 4 provides for
axisymmetrical illumination of the cylinder-shaped cell 8 by the
light beam 2, reflected from the elliptical mirror 7, and prevents
the illumination of the end face of the cylinder-shaped cell 8 and
the portion of the elliptical mirror 7 in immediate proximity to
said cell 8. A semi-transparent mirror 10 for dividing said light
beam 2 is interposed between the elliptical mirror 7 and the field
diaphragm 6 in the path of the light beam which is incident on the
eliptical mirror and reflected therefrom 7. The semi-transparant
mirror 10, is positioned at an angle to the axis of the eliptical
mirror 7, and directs the light beam 2 to the photoreceiver 11
which is arranged symmetrically to the field diaphragm 6 with
respect to the semi-transparant mirror 10.
The proposed device operates as follows.
The luminous flux, emitted by the light source 1, is shaped by the
condensor 3 and limited by the aperture diaphragm 4 into a light
beam 2 which then passes through the collective lens 5, field
diaphragm 6, and falls on the semi-transparant mirror 10. A portion
of the light beam 2 is reflected from the semi-transparant mirror
10 and thus is of no further use. The portion of the light beam 2,
which passes through the semi-transparant mirror 10, falls on the
eliptical mirror 7, and is then focused on the cylinder-shaped cell
8 containing the substance 9 to be photometered. The light beam 2,
which has passed through the cell 8, is partially absorbed by the
substance 9 therein and falls on the elliptical mirror 7 where it
is collected by said mirror 7 and partially reflected from the
semi-transparant mirror 10, whereafter it falls on the
photoreceiver 11. The photreceiver generates a signal proportional
to the amount of light which has passed through the cylinder-shaped
cell 8 containing the substance to be photometered 9, and the
signal is registered by an electronic circuit (not shown). The
cylinder-shaped cell 8 is simultaneously illuminated from all
radial directions crossing the focus of the elliptical mirror 7 and
limited by the action of the aperture diaphragm in the meridian
planes.
The working solid angle of the elliptic mirror 7, at which the
light is collected, after it has passed through the cylinder-shaped
cell, can be 90 percent of the full solid angle, and, therefore,
practically all the amount of light, which has passed through the
cell 8, or has been reflected therefrom, is collected and directed
to the photoreceiver 11. This helps to reduce the sensitivity of
said device to light diffusion in the substance 9 placed in the
cylinder-shaped cell 8.
The rotational symmetry of the illumination system, and, in
particular, of the elliptical mirror 7, and its coaxial disposition
with the cylinder-shaped cell 8 helps to reduce the light
sensitivity of said device to the positioning and imperfection in
the geometry or shape of the cell 8, and also fully eliminate a
change in sensitivity of the device to light absorbtion of the
substance 9 placed in the cylinder-shaped cell 8 with axial
rotation of said cell 8.
* * * * *